Larry Parsley, 73, is in jail after he was charged with 50 counts of child pornography. The Lake County Cyber Crimes Unit served a search warrant at his home and found pornographic pictures and video of children. Investigators knew he had the child porn before they even set foot in his home.

“Most of our cases, we have built our cases before we interview them, based on today’s technology,” said Sgt. Jim Vachon, Lake County Sheriff’s Office.

The Federal Internet Crimes Against Children Task Force says Florida ranks fourth in the nation in volume of child pornography. Because of that trend, cyber crime units have been popping up throughout the state.

Lake County would not talk about investigative techniques, but WFTV has learned file-sharing software is being used to track down suspects. Each person’s computer is assigned an IP address similar to a phone number. Detectives can sit at their desks, look at various IP addresses, and check to see if files with child porn have been downloaded.

In Parsley's case, investigators were able to link him to the IP address that downloaded child porn.

Defense attorney Will Jay says the new software makes it difficult to defend a client; investigators are able to build a strong case based on the words someone types.

“The electronic footprints you leave on the Internet is not very different from the DNA you leave at a crime scene,” Jay said.

In 2009, the Lake County Sheriff's Office reported 92 child porn cases and 27 arrests. The Attorney General's Office has also made a push against cyber crimes in less than two years. The unit has grown from a staff of six to 56.